Method for making thermographic copies from non-infrared absorbing originals



328i AVAiLABLE COPY "DEFENSIVE PUBLICATION UNITED STATES PATENT OEFICE Published at the request of the applicant or owner in accordance with the Notice of Apr. 11, 1968, 849 0.6. 1221. Identtn cation is by serial number at the application and the heading indicates the number of page: of specification, including claima, and o! IhQQtB'Of drawing contained in .the application a: originally tiled, The file of this application is available to the public for inspection; reproduction and: be purchased-tor 30 cents per sheet.

Application: publiahed under the Defensive Publication Program here not been examined as to the merits of alleged drivention. The Patent Olice makes no assertion a so the novcitr ot .the disclosed subject matter.

PUBLISHED DECEMBER 10, 1968 70$;476 METHOD FOR MAKING THERMOGRAPHIC COPIES FROM NON-INFRARED ABSORB- ING ORIGINALS Frank D. .Alien, deeeased,--late.-of Rochester, N.Y., by Mona Armstrong Allen, ex ecutrtx, Q55 IhornanDrive, Roehester,N.Y. s Filed Feb. 21, 1968. Published Dec. 10, 1968 Class 96-27 No Drawing. 10 Pages Specification A process is described for preparing thermograpbie copies from substantially non-infrared-absorptive original images. The process comprises exposing a photosensitive element to actinic radiation through the original, forming with the element an infra-red absorptive image and then employing this infrared absorptive -image as a second generation original in a thermographic copying process. In one embodiment an infrared absorptive image is pre- ,pared by employing as the photosensitive element a photothermographic element which undergoes a change in tackifying point upon photoexposure. After heating, cornpo'sition from areas having a lower taoltifying pointjs "transferred to a receiving sheet, if an infrared absorptive colorant is incorporated in the composition, or is toned with an infrared absorptive material. An example of a suitable photothermographic element is one containing a layer of a photosensitive copolyester composition con- *taining as an integral portion theiight-sensitive grouping 111a second embodiment an infrared absorptive imagc;is ,prepared by the image-wise photodestruction of a photo- "?oieachable dye, such as a polymethine pyrylium dye or a polymethine cyanine dye, contained in the photosensitive element. 

